Abstract: A process for the recovery of ethane, ethylene, propane, propylene and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. In recent years, the preferred method of separating a hydrocarbon gas stream generally includes supplying at least a portion of the gas stream to a work expansion device, then directing the work expanded stream to a distillation column at a mid-column feed point below an upper rectification section. The top column feed above the upper rectification section is typically a condensed and subcooled gaseous stream, frequently comprised of a gas stream that would otherwise feed the work expansion device. In the process disclosed, the work expanded stream is further cooled prior to feeding the distillation column at the mid-column feed point, so that a lesser volume of top column feed is required to maintain the column overhead temperature at a temperature whereby the major portion of the desired components is recovered.

Abstract: A process for the recovery of ethane, ethylene, propane, propylene and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. The stream is divided into first and second streams, and the second stream is expanded to the fractionation tower pressure and supplied to the column at a mid-column feed position. A recycle stream is withdrawn from the tower overhead after it has been warmed and compressed, and is combined with the first stream. The combined stream is cooled to condense substantially all of it, and is thereafter expanded to the fractionation tower pressure and supplied to the fractionation tower at a top column feed position. The pressure of the compressed recycle stream and the quantities and temperatures of the feeds to the column are effective to maintain the column overhead temperature at a temperature whereby the major portion of the desired components is recovered.